Method and apparatus for treating rayon



METHOD AND APPARATUS FOR TREATING RAYON Filed Jan. ll, 1934 INVENTORLQUKS S. FRYE Patented Apr. 21, 1936 UNETE STATES PATENT OFFIE METHODAND APPARATUS FOR TREATING RAYON 7 Claims.

This invention relates to the manufacture of artificial silk, and moreparticularly to the pot spinning process for the production ofartificial silk from viscose. In said process the multiple filamentthread, after coagulation, is led to and wound or formed as a hollowgenerally cylindrical cake in the spinning pot, following which thethread is washed, desulfurized, bleached, and otherwise treated,culminating in the usual drying operation with the thread ready fordyeing, knitting, or weaving operations.

My invention is designed to provide improved method and apparatus bywhich the thread wound in and removed from the centrifugal pots may besubjected to any or all of the usual treatments in the most efficientand satisfactory manner, not only by convenient and rapid operationswhich reduce the amount of handling to which the material is subjectedand therefore avoid breakage and injury to the fiber or thread, but alsoby practices which insure a uniform effect upon all parts of the thread,giving it desirable characteristics as regards dyeing properties,strength, luster and the like.

One object of the invention is to provide apparatus including a holderor support forthe cake which enables air or treating liquids or baths tobe moved through the hollow cake in either or both of the two possibledirections, towit, either from the outside inwardly or from the insideoutwardly, and in a manner to always insure application of the air ortreating liquids to all parts of the cake, to avoid icy-passing or flowof the liquids or air around and not through the cake, and to insureuniform treatments of all parts of the cake with uniform and evenshrinkage upon drying.

A further object of the invention is to provide an improved inner liner,of cuff form, upon which the cake is sleeved and supported duringtreatment, said liner being self-accommodating to any variations ininner diameter of the cake not only to take account of minor variationsin diameter but also to receive unusually short doffs, and which also isprovided with perforations or openings so arranged that regardless ofthe inner diameter of the cake uniform and free flow of material isprovided to all parts of the cake.

A further object is to provide holding or supporting means for rayoncakes of this type which is self-accommodating to the length of the cakealong its axis from end to end, with the ability to accommodate itselfto either shrinkage or expansion lengthwise during any of the treatingoperations or during drying, and in a manner to seal the cake at bothends against the production of short cut paths by which the liquor orair may pass around the cake without application to its fibers, andfurther, such an apparatus which is automatic in operation and requiresno special attention from the operator.

A further object of the invention is to provide anim-proved method oftreating rayon cakes of this kind in a simple and expeditious manner andso as to insure uniform characteristics of the thread by causing thetreating liquid or air to flow alternately inwardly and outwardlythrough the cake walls so that all parts of the cake receive liketreatment and the thread has uniform characteristics from end to end,all in the manner to accomplish any or all treatments to which thethread is to be subjected from the time oi its initial setting up orcoagulation clear through to and including the drying operation.

Further objects of the invention are in part obvious and in part willappear more in detail hereinafter.

In the drawing, which represents one suitable embodiment of theinvention, Fig. 1 is a sectional elevation, partly diagrammatic, showinga cake in position for treatment; Fig. 2 is a perspective view of theliner; Fig. 3 is a similar view of the assembled cake and liner; Fig. 4is a sectional plan view on the line 44, Fig. 1; Fig. 5 is a sectionalView corresponding to Fig. 1, and illustrating the manner of handlingshort doffs; and Fig. 6 is a similar view illustrating a modificationfor handling a plurality of cakes.

Referring to Fig. 1, A represents the rayon or artificial silk cake asproduced by the spinning 35 operation in the pot or bucket process. Thethread is produced from viscose with the use of usual reagents and thecake is produced in a rotating pot along the axis of which the thread isdelivered from a feeding device, the rotating mo- 40 tion causing thethread to fly outwardly and pile up inwardly against the wall of the potuntil the spinning operation is concluded. The cake itself, generallyspeaking, is of hollow cylindrical form, although it is usually somewhattapered from end to end to enable it more readily to be removed from thepot. The outer diameter and form is controlled by the shape of the potitself and particularly by the form of the inner surface of the potwall. The length of the cake depends upon the length of travel of thetraverse mechanism and its thickness upon the length of the thread spuninto cake form. This thread length in normal operations is more or lessuniform, the cake being half an inch to an inch and a half in thicknessand from four to six inches long depending upon conditions establishedin the plant, but if the thread breaks during the spinning operation orif the doif, for any reason, is terminated earlier than usual, the cakemay be considerably thinner than usual and is known as a short doff. l i

Upon conclusion of the spinning operation the cake, in wet form, isremoved from the pot and is applied to a supporting liner which, in thepresent instance, is of substantially cylindrical cuff-like form, buttapered to correspond tothe taper of the cake, as will be readilyunderstood. Such a cuff-like liner or support is illustrated at I, Fig.2. It is made of suitable non-corrodible material, such as aluminum,rubber, etc., in relatively thin sheet form and with sufficient yield,inherent strength and resiliency to yieldingly resist inward. collapseas the result of pressure upon it by shrinkage of the cake or otherwise.Circumferential dimension of the liner is such that when it is within acake, as in Fig. 3, the longitudinally extending edge portions have amaterial overlap upon each other, as indicated at 2, the overlap beingsuihcient so that the cuff may be either contracted to fit a normal cakeor expanded to accommodate itself to a short doff with a larger internaldiameter, and the edges themselves of course are smoothed or rounded outso as not to injure the fibers.

This cuff, while it supports the cake, must nevertheless be of a form toenable treating liquids or air to travel through the cake in the radialdirection, for which purpose it is perforated, but the perforationsconsist of two series of slots or elongated openings 3, l, one setextending in the circumferential direction around the cuff and the otherat a suitable angle thereto, such as longitudinally along it. Therefore,where the adjacent longitudinally extending edge portions of the cuffoverlap the two sets of circumferential and longitudinal slots overlieeach other, insuring the presence of through openings in thisoverlapping zone regardless of the size to which the cuff is expanded orcontracted, and avoiding any possibility of blocking penetration ofliquor or air through the overlapping portions in particular adjustmentsof its size, as is the case when the openings are simple round holes.

The cuff itself is made longer than the particular size of cake withwhich it is to be used, the excess length being desirable for subsequentconnection of the dry cake mounted on the cuff to a coming, reeling, orother textile machine.

Upon removal of the cake from the spinning pot and its application to acuff or liner in the manner described, the cake and cuff together aremounted in supporting apparatus where subsequent process steps areperformed upon the yarn. Such supporting apparatus is more or lessconventionally shown in Fig. 1. It comprises a suitably supported casingor shell 5, shown as of box-like form to serve as a receptacle forliquid, and closed by a cover ii, which may be sealed to the casing inany manner to produce a tight joint, such as is necessary when pressureor vacuum are employed. In the arrangement shown, the cover is sealed tothe casing by gaskets "I against which it is yieldably clamped bysprings 8 beneath a clamping bar 9 hinged at It and releasably locked inplace by the hasp II, although any other clamping arrangement may beemployed. By releasing hasp I I the clamping bar may be raised and thecover removed.

Within the casing 5 is a base or platform I2 having an opening in itscenter to which a coil duit I3 is connected, the joint being sealed by anut I3a and sealing gasket or washer l3b. Surrounding the opening theplatform is provided with a pilot and liner supporting member includingwing-like portions I4 and with a sealing gasket or seat member I5, madeof rubber or other suitable material, and which at its center is cutaway or otherwise formed to produce a recess If to receive theprojecting end of the cuff or liner I. The cuff or liner with the cakeupon it is laid in place in the manner shown in Fig. 1, with the cakeresting directly upon gasket I5 and the cuff entering recess I6. Thecover 6 is provided on its under surface with a head or upper clampingmember II, which in form is generally similar to the base I2, havingpilot Wing portions I8 at its center designed to enter and support theother end of the cuff I, while outside of the pilot portions the headmember II is provided with a sealing gasket I9 which again may be ofrubber or like yielding material. In this case the wings I8 are soformed that there is a gap or space 28 between the inner edge of thegasket 59 and the wings I8 to receive and support the projecting end ofthe cuif I, and the parts are so proportioned, with relation to thelength of the cake A, that both ends of the cuff I stop short of seatingat any time against any rigid portion of the base I2 or head I'!. HeadII is connected to the cover by a suitable yielding compression means,such as the spring 2| surrounding a rod 22 extending through the coverand provided outside of the cover with means for adjusting the springpressure, such as the nut 22a.

The drawing shows the cake applied to its seat in the casing 5 with itssmall end down, but this is not essential as the parts may be arrangedto receive the cake with its small end up, as will be readilyunderstood.

Outside of the base I2 the casing 5 is also provided with connections toa second conduit 23 and of course it will be understood that the casing5 may be made large enough to contain a plurality, even a large numberof supports for individual cakes and cuffs of the kind illustrated inFig. 1. In other words, the chamber 24 may receive and contain aplurality of cakes, with a separate supply pipe I3 to the cavity 25within each cake and with one or more pipes 23 connected to the chamber24.

Moreover, a plurality of cakes may be piled one upon the other orarranged in axial alinement, in the general manner illustrated in PaleyPatent 1,779,103, October 21, 1930, in which case, as illustrated inFig. 6, each head I! not only carries a pilot III for the upper end ofthe cake beneath it, but also serves as the base I2 for the cake nextabove it, carrying a pilot I4 to enter its lower end, and theintermediate separating members between cakes in this case areperforated or provided each with a through opening 26 so that each pipeI3 communicates openly with the chamber within each of the endwisealined cakes connected with it. Such an arrangement, however, is usuallynot so satisfactory as that shown in Fig. 1, due to increasing weightand pressure upon the lower cakes as cake is piled upon cake, as will bereadily understood.

In operation, the spring M is adjusted to such a compression that whenone or more cakes, each mounted upon a cuff, are laid in position asshown in Figs. 1 or 6, and the cover 6 is sealed upon the casing 5, eachcake is supported between two gaskets I5, I9 which contact with andtherefore seal its opposite ends, although the gaskets are applied witha light pressure which has no tendency to harm or injure the fiber.Moreover, the gaskets are clamped to the opposite ends of the cake by alight pressure which is adjustable and also self-accommodating to anyendwise expansion or contraction of the cake or cakes as a whole.Experience shows that in some plants practicing the pot spinning processthe cakes actually expand during some of the treatments, whereas inother plants the same treatments cause the cakes to contract. Indeed,expansion and contraction may occur during the same process but indifferent stages, expansion occurring in I the first steps andcontraction following as the purification proceeds, the contractionbecoming quite pronounced during drying. Whatever be the conditions andwhatever be the process step performed, the spring 2| always exerts alight pressure endwise upon the cake, sealing the gaskets to it with aself-accommodating adjustment or movement of each head I'l back andforth to take account of either expansion or contraction, and allwithout conscious attention on the part of the operator.

both directions inwardly and outwardly.

Having seated the parts in the position shown in Fig. 1 or 6, the cakeis now subjected to the necessary treating operations, such as washingto remove excess acid, desulfurizing, bleaching. dyeing or the like,with intervening washings where necessary. The treating material,whether it be air or wash water, desulfurizing bath, bleaching bath, orany other liquor, is passed through the cake by use of the pipes I3, 23,which are connected by valves 21, 28 to supplies of such liquids orbaths and to a pump system (not shown) for repeatedly circulating thesame, if desired. Suitable valves (not shown) may be provided forreversing the direction of flow, and in the usual treatment the bathliquor may be caused to flow in one direction for a short period, say afew minutes, and then in the opposite direction for a like period, andso on until the operation is completed. By this method uniformity ofeffect upon all parts of the thread in the cake is assured, asdistinguished from those arrangements in which the flow of liquorthrough the cake is always in one direction. For example, in thebleaching operation, when the bleaching bath always flows from theinside outwardly, the degree of bleaching effect is always greater alongthe inside of the cake than it is along the outside of the cake, becausethe inside of the cake always encounters a bath of full strength and theoutside of the cake always encounters a bath of reduced strength. Whenthe direction of flow is reversed, the gradation in effect in onedirection is balanced against the gradation in effect in the otherdirection, resulting in an average effect which is uniform throughoutthe package.

The cake of course is applied to its cuff and is placed in the treatingapparatus as shown in Fig. 1 in wet form, and all treatments with wateror bath liquors are performed in succession while the cake is still wetand without permitting it to dry, and further, without any necessity fortransferring it from place to place. Consequently, breakage or injury tothe thread by unnecessary handling is avoided.

When all treatments with water or liquor baths have been completed, thecake is now dried by passing dry or heated air through it. Preferablythe air is caused to travel from the outside of the cake toward itscenter. The air may be supplied by way of pipe 23 and may be exhaustedby way of pipe 13. When it travels in this direction, uniform shrinkageconditions upon drying are insured, because the outer layers of the cakedry first and drying continues toward the center of the package. As.shown in the drawing, the outer edges of the pilots 18, where they.

engage the ends of the cuff,. are very slightly tapered, in addition towhich the cuff itself is tapered. When the apparatus is first assembledwith a cuff in place upon the pilots, preparatory to cake treatment, thecuff may engage the pilots rather loosely. However, as the treatmentproceeds, particularly during drying, the cake as a whole shrinksendwise and the spring 2| expands to advance the end heads toward eachother, forcing the pilots more and more intothe ends of the cuff, withan increasing tendency to positively resist contraction thereof.Therefore, referring particularly to the drying operation, when air ispassed through the cake radially inwardly, at first each of the outerlayers of thread dries against the tension of a relatively non-yieldablewet cake with some slight shrinkage of the cake both radially andendwise. The pilots are pushed into more intimate and more firmlysupporting engagement with the cuff and the last layers of thread dryagainst a similarly non-yielding body, to-wit, the cuff or insert. Thisoperation is fundamentally quite different from that which occurs in theusual practice where the air current is caused to travel from the insideof the cake outwardly. Here the first layers to dry do so against arelatively nonyielding body-the cuff or insert-- and as drying proceedsto the outer layers these layers have more and more room to shrinkbecause the previous layers have already shrunk in drying. Thus, in thepreferred method, the entire length of yarn dries and shrinks under thesame tension conditions, while in the usual method the yarn dries andshrinks under varying tension conditions with a consequent production ofvarying yarn characteristics as regards dyeing properties, luster,strength, etc. If the cake is dried in the usual conventional manner,that is, when placed on a truck and dried in a chamber, all of theexposed surfaces of the cake dry first; the outer layers and the yarn onboth ends dry against the wet cake and therefore shrink very little, butthe inner layers dry against an unsupported cuff or insert and shrinkmore while. the layers in the center of the cake thickness which arelast to dry shrink most. Thus the yarn acquires serious variations inits properties which manifest themselves as barre, railroad tracks,shiners, etc.

When the doff is short or when, in other words, the cake is not of fullthickness, as shown in Fig. 5, it may nevertheless be treated in thepresent apparatus. Of course, with such short doff and therefore thinnercake, the cuff must be expanded to a larger diameter at both ends thanwith a full thickness cake, as in Fig. 1. Therefore, the projecting endsof the cuff would abut endwise against the sealing washers I5, l9. Ac-

cordingly, to receive and accommodate thin cakes produced from shortdoffs, special washers [5a, I So are employed, such washers having thesame external but having increased internal diameter except at the baseflange. Otherwise the operation with a thin cake is the same as before,the benefits derived from the preferred method of drying not being fullyachieved, however. Nevertheless, such short dofis may be well dried bypassing the air current from the inside of the cake toward its outside,when again fairly uniform conditions are insured, the reason being thatthe liner is now not internally supported by the pilots and is thereforeyieldable, so that each layer dries with yieldable material beneath it.

While the drawing illustrates the cakes mounted in the treatingapparatus with their axes lying vertically, it will nevertheless beunderstood that such an arrangement is not essential, as the parts maybe so arranged as to support the cakes in the horizontal or any otherposition.

What I claim is:

1. Apparatus for treating wet, freshly spun, hollow, generallycylindrical rayon cakes, comprising cooperating end heads provided withseats to receive the ends of the cake, means for yieldingly pressingsaid end heads toward each other to permit self-accommodation of the endheads to either endwise expansion or endwise contraction of the cakes,and a resilient expansible perforated liner of generally tubular formwithin the cake and projecting from each end thereof, the end headshaving cavities of surficient depth to receive the projecting ends ofsaid liner without abutment of the end heads against the liner ends uponmaximum endwise cake shrinkage, and means for causing the flow oftreating fluid radially through the cake..

2. Apparatus for treating wet, freshly spun, hollow, generallycylindrical rayon cakes, comprising cooperating end' heads provided withseats to receive the ends of the cake, means for yieldingly pressingsaid end heads toward each other to permit self-accommodation of the endheads to either endwise expansion or endwise contraction of the cakes,and a resilient expansible perforated liner of generally tubular formwithin the cake and projecting from each end thereof, the end headshaving cavities of suflicient depth to receive the projecting ends ofsaid liner without abutment of the end heads against the liner ends uponmaximum endwise cake shrinkage, and means for causing the flow oftreating fluid radially through the cake, each end head having a pilotentering one end of the liner and adapted to engage and resistcontraction thereof as the treatment proceeds.

37 Apparatus for treating wet, freshly spun, hollow, generallycylindrical rayon cakes, comprising a hollow casing provided withopposed end heads each provided at its center with a pilot, one of whichpilots has a through opening for the flow of fluid therethrough, aresilient yielding perforated liner of generally tubular form having itsend portions sleeved over the opposed pilots, a seat member surroundingeach pilot and at its inner edge spaced therefrom to form a cavity toreceive an end of said liner, said seat members being adapted to beapplied to the ends of a rayon cake supported by the liner and thecavities being of sufficient depth to prevent abutment of the liner endswith the end heads upon maximum endwise cake shrinkage, and means foryieldingly moving the end heads toward each other to maintain uniformsealing pressure of the seat members upon the cake ends throughout thetreatment.

4. A liner for insertion into wet, freshly spun, hollow, generallycylindrical rayon cakes, comprising a thin sheet-like member havingoverlapping end portions and provided with perforations distributed overits entire area, the perforations in the overlapping end portions beingof elongated form and the perforations in one end portion extending atan angle to the perforations in the other end portion. 7

5. A liner for insertion into wet, freshly spun, hollow, generallycylindrical rayon cakes, comprising a thin sheet-like member havingoverlapping end portions and provided with perforations distributed overits entire area, the perforations in one end portion extendingcircumferentially of the liner and the perforations in the other endportion extending longitudinally of the liner.

6. The method of drying wet, freshly spun, hollow, generally cylindricalcakes of rayon, consisting in passing drying air radially through thecakes while subjected at both ends to a sealing pressure which ismaintained uniform throughout the drying operation and thereby seals thecake ends against any direct exposure to the air current, producingyielding resistance to contraction over substantially the entire innersurface of the cake, and as the drying effect approaches the cakeinterior gradually increasing said resistance, whereby the threadlayers, in order from the outside to the inside, shrink undersubstantially uniform conditions.

7. Apparatus for treating wet, freshly spun, hollow generallycylindrical rayon cakes, com prising cake supporting means includingmeans for applying and maintaining uniform sealing pressure to both endsof the cake during the entire treating operation, means for applying tosubstantially the entire inner surface of the cake yielding resistanceto cake contraction, means for gradually increasing said resistance asthe treating operation proceeds, and means for causing the flow oftreating fluid radially through the cake.

LOUIS S. FRYER.

